In an ink jet type recording apparatus in which a nozzle is used to jet ink droplets to print characters and images on a recording sheet, the nozzle opening is considerably small. Hence, if foreign matter such as paper dust sticks on the nozzle or bubbles are formed in the ink supply line, the ink droplets are not satisfactorily formed, and hence the resultant print is low in quality.
In order to eliminate this difficulty, an improved ink jet type recording apparatus has been proposed (EP-427202A). This recording apparatus has a restoring device for forcibly purging ink to remove foreign matter or bubbles from the ink flow line, and an externally operated switch to activate the restoring device. That is, the recording apparatus is designed so that, when the resultant print is unsatisfactory in print quality, the switch is operated to activate the restoring device, thereby to restore the printing operation.
The restoring device is used also in the case where the recording head is replaced with a new one, or the ink tank is replaced with a new one, or the recording apparatus is not used for a long time. That is, in these cases, it is used to purge ink for adjustment of the ink flow line.
On the other hand, a recording head is filled with a maintenance solution when shipped from the factory. Therefore, before a new recording head is used, it is essential to completely remove the maintenance solution from the recording head. For this purpose, a large quantity of ink is purged through the new recording head when compared with the quantity of ink purged from the ink flow line.
The ink thus discharged for replacement of the recording head or for restoration of the proper printing function is sent to a waste ink tank provided in the recording apparatus body. The waste ink tank is limited in volume because the casing of the recording apparatus body is also limited in space.
The above-described restoring operation is essential for maintaining the print quality high. However, if it is carried out repeatedly in an excessive fashion, then not only is a large quantity of ink wasted, but also the ink leaks from the waste ink tank which is limited in volume.